Outline  the role of regional anaesthetic techniques  in the management of pain  in the critically ill.

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College Answer

Many candidates provided long lists of regional techniques, but did address the issues of when to use and when not to use a technique. Consider asking “why don’t we perform more epidurals in our patients?”.

Advantages of regional anaesthetic techniques include

•    reduced narcotic use to achieve analgesia– less respiratory depression, especially in chest injury or high risk of respiratory failure (elderly, COPD, etc)

•    less ileus (reduce risk of aspiration, tolerance of enteral feeds, etc)

•    less interference with mental status (harder to attribute obtundation to drugs or injury)

•    reduces use of non narcotics, eg NSAIDS (renal impairment, platelet function); tramadol (confusion in elderly); paracetamol – all just adjuncts anyway and less efficacious than regional in severe pain; ketamine – hypertension, tachycardia, dissociative effects, etc)

Disadvantages (general)

•    often redundant in sedated, ventilated patient

•    not proven in critically-ill to be any better in terms of outcome in critically ill patients – thus not a lot of strong evidence to support use in critically ill over above alternatives

•    problems with local anaesthetic toxicity fairly uncommon with newer agents given by infusion (eg ropivacaine via epidural) – but some other regional blocks (eg brachial plexus catheters, pleural catheters, etc can get to higher dosages and greater risk of toxicity)

•    may still need narcotic adjuncts

•    technical expertise required

•    difficulty covering multiple sources of pain

•    sympathetic blockade, problems with coagulopathy, need for patient positioning, anatomical landmarks may be difficult

•    catheters over longer term => risk of infection. Also confused patients more likely to dislodge them

•    monitoring of blockade in uncooperative patient may be impossible

•    removal with DVT prophylaxis may be an issue

Disadvantages (local)

•    related to sites of placement – eg vascular injection, pneumothorax, other neuro injury, etc, etc. Also neuro blockade in presence of “uncleared” neurological injury and following plastic surgery for nerve injury.

Discussion

It is difficult to lump epidural and other regional techniques together.

So, I un-lumped them, for largely cosmetic reasons. 

Advantages and Disadvantages of Regional Anaesthesia in the ICU

Epidural

Peripheral nerve block

Advantages

  • Analgesia is better than with PCA
  • Better MIP (maximum inspiratory pressure) than with PCA
  • Overall improved respiratory function
  • More rapid weaning from ventilator
  • Avoidance of sedation
  • Less delirium
  • Less  risk of respiratory depression
  • If local anaesthetic used alone, possible to avoid opiate side effects
  • Lower incidence of DVT
  • Good pain control when the injury is localised
  • Avoids systemic effects of opiates
  • Avoids sympatholytic effects of epidural
  • Usually safe

Disadvantages

  • Requires skill for placement
  • Not   always   effective   (can   get patchy block)
  • Hypotension       may      require excessive fluid administration or pressor support
  • May   mask   other   associated injuries,  e.g.  ruptured  spleen  in this case
  • Risk of epidural haematoma
  • If opiate used in epidural infusion, opiate side effects such as itch, nausea, still a problem.
  • Redundant in the sedated patient
  • Requires a skilled operator to insert
  • Risk of intravascular injection
  • Difficult to cover multiple sites of pain
  • Redundant in the sedated patient
  • Risk of infection from infusion catheter
  • Risk of dislodgement with confused patients

References

References

Wu, Christopher L., et al. "Thoracic epidural analgesia versus intravenous patient-controlled analgesia for the treatment of rib fracture pain after motor vehicle crash." Journal of Trauma-Injury, Infection, and Critical Care 47.3 (1999): 564-567.

 

MACKERSIE, ROBERT C., et al. "Prospective evaluation of epidural and intravenous administration of fentanyl for pain control and restoration of ventilatory function following multiple rib fractures." Journal of Trauma-Injury, Infection, and Critical Care 31.4 (1991): 443-451.

 

Kieninger, Alicia N., et al. "Epidural versus intravenous pain control in elderly patients with rib fractures." The American journal of surgery 189.3 (2005): 327-330.

 

Moon, M. Ryan, et al. "Prospective, randomized comparison of epidural versus parenteral opioid analgesia in thoracic trauma." Annals of surgery 229.5 (1999): 684.

 

Jarvis, Amy M., et al. "Comparison of epidural versus parenteral analgesia for traumatic rib fractures: a meta-analysis." OPUS 12 (2009): 50-57.

 

 

Scherer, R., et al. "Complications related to thoracic epidural analgesia: a prospective study in 1071 surgical patients." Acta anaesthesiologica scandinavica 37.4 (1993): 370-374.

 

Kapral, Stephan, et al. "The effects of thoracic epidural anesthesia on intraoperative visceral perfusion and metabolism." Anesthesia & Analgesia 88.2 (1999): 402-406.